6.5 month old crestie not gaining weight

I could use some advice here while I wait for my vet to call me. I got a 5 month old crested gecko back in early November and I didn't realize at the time but she has some issues. The big one is that she is, well, not getting bigger.

I weighed her shortly after I got her and my scale (which unfortunately is only accurate to 1 gram) reading was bouncing between 2 and 3 grams. She saw my exotics vet 3 weeks later to establish care, they weighed her at 2.4 grams, which they were rather concerned about as that's hatchling size, but she was almost 6 months old then. The vet said we'd just monitor her weight and make sure it's trending the right direction, which seemed wise as she's eating her Pangea growth and breeding pretty much daily, with a bit of another flavor mixed in for variety. 3 weeks later (yesterday) I weighed her again at home. This time she's reading 2 grams, no number bouncing.

I tried reaching out to the breeder and it was not much help, she stated that my gecko looks "chunky" in the photos (she literally doesn't, you can see her effing ribs through her skin), tried criticizing my husbandry, and suggested feeding twice a day and giving her mealworms. Y'all, she has food available at all times, replaced every 24 hours with a "refresh" halfway through the day, to make sure it doesn't dry out. There were a few days where she suddenly stopped eating, and I realized it was probably that she wasn't finding her food anymore, so I immediately added a hanging ledge where she hangs out most frequently and she started eating again. Now she actually will sit on the cup and ledge waiting for food to magically appear because she knows that's where it goes. My vet didn't recommend feeding bugs yet because she's so tiny he worries she'll get impacted. He also can't do a fecal exam for parasites because her poops, while normal in appearance, are just too small for a sample size. Despite everything, he told me this gecko is in excellent hands with me, my husbandry and research are spot on as far as he's concerned.

So what else can I do here? I am so worried she is gonna die on me, I've only had her for 6 weeks but I would be heartbroken if I lost her.

Tl;dr: crestie was sold to me at 2.5 grams and she still is that weight despite being 6.5 months old. Is eating pangea growth formula and pooping normally, but still not putting on weight. Vet can't do fecal exam until she gets bigger, also doesn't recommend feeder insects yet due to size. What else can I do to put some weight on her?